This invention relates to a method of electrolytically treating a metal sheet, and to apparatus for the use in this method. In particular, but not solely, it relates to tin-plating a steel sheet.
Hot dip tinning has been virtually superseded by electrolyte pin-plating, which can produce thinner tin coatings of excellent quality. Typical of modern tin plating are the "Halogen" process and the "Ferrostan" process. Both of these processes treat steel strip at the rate of 1,400 - 2,000 ft/min (totalling 140,000 to 200,000 tons per year) and involve a large capital investment.
However, particularly in the developing countries, there are many circumstances in which it would be desirable to be able to tin-plate individual sheets continuously (rather than batch-wise) at the rate of, say, 10,000 to 20,000 tons per year with comparatively simple and inexpensive equipment. It would also be desirable to be able to electrolytically treat individual sheets continuously, but up to now no satisfactory technique has been developed, despite considerable research.